The objective of the study was to develop a test of concept formation which would: (1) not be biased by reading difficulty; (2) be sufficiently stimulating to capture the attention of the students; (3) incorporate both aspects of concept formation of discriminative response and conservation; (4) have a spread of item difficulty appropriate for students in grades 2, 4, and 6; and (5) follow a group administration format. The final form of the test consisted of 34 items, 21 on conservation and 13 discriminative response items. The conservation items were presented via an 8mm film with accompanying sound. The 13 items were presented in a booklet, with one item per page. The types of conservation included in the test were number, length, discontinuous quantity, continuous quantity, mass, area, weight, and volume. Results of administering the test show group film testing to be a valid and reliable method of testing concept formation. (DB)